Mold for making filter-pads.



PATENTBD SEPT. 15; 1903 No; 739,087. I

t 4 E uL-KNIGHT.

MOLD FOR MAKING FILTER PADS.

APPLICATION FILEDAPR. 29, 1903.

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V fwflafla vgwg I flttowm UNITED STATES Patented September 15, 1903.

PATENT OFFICE.

EDWARD MARTIN KNIGHT, or BROOKLYN, NEW YORK, ASSIGNOR or one HALF TO B.H.'MARTIN, on NEW YORK, N. Y.

MOLD FOR MAKING Fl LTER-PADS.

SPECIFICATION forming part of Letters Patent No. 739,087, datedSeptember 15, 1903.

I Application filed'April 29, 1903.}

Serial No. 154.779- (No model.) I

To all whom it may concern.-

Be it known that I, EDWARD MARTIN KNIGHT, a citizen of the UnitedStates, residing at Brooklyn, in. the county of Kings and State of NewYork, have invented new and useful Improvements in Molds for -MakingFilter-Pads, of which the following is a specification.

This invention relates to certain new and useful improvements in devicesfor making pads or diaphragms of fibrous material for separatingsedimentary matter from water designed for drinking and domesticpurposes; and the invention consists, essentially, of a mold comprisinga holder and opposing fabric-surfaced dies, between which the pad isformed.

The invention also consists of a pair of dies and a spacing ring ormember surrounding the edge of one of the dies and adapted to reduce thespace between the outer edge portions of the pair of dies when one ofsaid dies is forced toward the other to compress the mass of fibrousmaterial placed between them, as I will presently describe.

The invention further consists of the'parts and the'constructions andcombinations of parts, which I will hereinafter describe and claim.

In the accompanying drawings, forming part of this specificationandinwhich similar letters of reference. indicate like parts, Figure 1 is avertical sectional view of a mold embodying my invention. Fig. 2 is aplan. View of one of the dies. Fig. 3 is a plan view of thespacing-ring. Fig. 4is a sectional View. of a mold of modified form.Fig. 5 is a modification to be referred to.

The object of my invention is to form the filter-pad of fibrousmaterial, such as asbestos, and to form the said pad with one portionmore compact or dense than the remaining portion, said dense portionbeing, however, sufficiently porous to permit the percolation of waterthrough it, during which percolation the water is relieved of itssedimentary or suspended particles. In the per- 1 for efiectivefiltration purposes. This mold may be of a varied character, and itssize and interior shape will depend upon the size and form of thedesired pad. I

In Fig. 1 the mold is shown of circular form and comprises a holder Awith deep surrounding flange A and a central opening A in its bottom tofacilitate the removal of the hereinafter-described dies and thefinished or compressed pad. In the bottom of the holder A, I place thelower die B, whose diameter approximates that of the holder, said .dieconsisting, preferably, of a metal disk or plate, over the upper surfaceof which is stretched a piece of. fabric B,whose edge is turned over thedisk or plate and appropriately secured by a binding-strip B Inconnection with this lower die I usean upper or companion die 0 of likeconstruction, over the under part or face of which is the fabric surface0', secured by a surrounding bindingstrip '0 In addition to theforegoing I employ a loose fiat ring D, whose outer diameter is aboutequal to the diameter of the dies and whose inner diameter is aboutequal to the diameter of that portion of the pad which might beconsidered theactive portion exposed to the direct action of the watertobe filtered. This ring is laid upon the lower die and fibers ofasbestos or other suitable material which have been carded or combed andare placed within the holder on top of the ring and lower die. Asufficient mass (determined, for instance, by weighing) is placed withinthe holderand lies upon the fabric-covered surface of the lowerdie,which surface has been previously moistened to prevent the fibersadhering to it. Then the upper die, whose fabric surface has also beenmoistened, is placed upon the mass of loose fibers, and pressure isapplied to said upper die by a plunger E or other pressure device whichmay represent a member of a suitablepress, and the. mass of fibers iscompressed to the desired degree between the opposing faces of the dies.ring D serves to space the distance between the peripheral portions ofthe dies, and when the aforesaid pressure is applied to the upper diethe mass of fibers is forced into the space represented by the opencenter of the ring The VII

fibers sticking to the fabric of the dies.

and reduced in thickness and compressed; but as the ring projects abovethe plane of the face of the lower die it will be apparent that theportion of fibers which overlie the ring will be subjected to a greaterpressure, and therefore made more dense and compact than the fiberswhich occupy the space in and above the open center of the ring. Theresult is, therefore, that the central portion of the pad is left lessdense and compact than the edge portion, and this less dense portion or.part subjected to less pressure adjacent to the edge portion subjectedto greater pressure may then be bent over the sharp angles of afilter-frame without danger of rupturing the pad and opening up crevicesfor the passage of unfiltered water.

In some instances it is desirable to compress the central portion of thepad to a greater degree than the edge portion, as disclosed in myapplication, Serial No..1l6,123, filed March 4, 1903, and when this isdesired the loose ring is omitted and the central portion of both diesare thickened, as at E, thereby forming surrounding edge portions ofreduced thickness. In this case, as the central portions of the dies arethicker than the edge portions and stand beyond the plane of the latter,it will be manifest that when the pressure is applied, as aforesaid,said thickened central portion will sink more deeply into the mass offibers and will consequently more firmly compress the central portion ofthe mass of fibers than the edges, as the latter will occupy the greaterspace formed by the thinner edge portions of the dies and willaccordingly be subjected to but little compression, so that the fibersmay be left substantially loose. In either of the above instances thefinished pad will show a decided bead at the junction of the compressedcentral portion with the less compressed and soft and pliable edgeportion, which enables the'latter to beturned or bent at one or moresubstantially sharp angles to the more solid central portion, as whenputting the pad into a filterframe and bending the soft edge to form awater-tight joint with said frame.

When the pad has been compressed, as before described, the dies and padare removed from the holder by pushing the finger or a tool through thehole in the bottom of the holder, and thus lifting the dies and pad, andsaid dies are then removed from the pad,their moistened surfaces havingprevented the The pads are then packed in boxes or packages ready foruse in filter-frame of suitable size and form.

If desired, the ring may be made rigid with one of the dies, as shown atFin Fig. 5, without departing from the spirit of my invention.

Having thus described myinvention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a device of the character described,the combination with a holderadapted to receive fibrous material, of upper and lower dies betweenwhich the material is compressed,said lower die having a facing ofmoisture-retaining material. I

2. In a device of the character described,the combination with a holderadapted to receive fibrous material, of upper and lower dies betweenwhich the material is compressed said upper die having a facing ofmoisture-retaining material.

3. In a device of the character described,the combination with a holderadapted to receive fibrous material, of upper and lower dies betweenwhich the material is compressed said dies having a facing ofmoisture-retaining material.

4. In a device of the character described,the combination with a holderadapted to receive fibrous material, of opposing flat-faced dies looselyplaced within the holder and between which the material is compressed,and means proportioning the pressure upon said material whereby oneportion of the mass of material is compressed to a greater degree thanthe remaining portion.

5. In a device of the character described,the combination of a holderadapted to receive fibrous material; opposing dies between which saidmaterial is compressed; and means upon one of said dies and extendingbeyond the plane of the face thereof for subjecting one portion of thematerial to greater pressure than the remaining portion.

6. In a device of the character described,the combination of a holderadapted to receive a mass of loose fibers; a removable die in saidholder; a ring surrounding the periphery of the die, upon which ring anddie the fibers lie; and a second die opposing the first-named one saiddies having a fabric covering over their opposing faces.

7. In a device of the character described,the combination of a holderand upper and lower dies one of said dies seated in the bottom of theholder said holder having an opening in its bottom to facilitate theremoval of the dies.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

EDWARD MARTIN KNIGHT. Witnesses:

H. D. J AMESON, A. NORTH.

